GENETICAL LINKAGE RELATIONSHIPS OF DDT-RESISTANCE AND DIELDRIN-RESISTANCE IN CULEX PIPIENS FATIGANS WIEDEMANN

Abstract

The tropical house mosquito Culex fatigans readily develops resistance to DDT and to dieldrin and hexachlorocyclohexane. Studies of the mode of inheritance of these 2 types of resistance in material from Rangoon selected to a high resistance level showed DDT-resistance to be due to a single principal gene which was almost completely dominant and dieldrin-resistance to be due to a single gene allele neither dominant nor recessive, the hybrids being intermediate. The DDT-resistance factor was linked with the chromosome-2 marker genes y (yellow larva) and ru (ruby eye), at crossover distances of approximately 20 and 45 percentage units respectively. The dieldrin-resistance factor was linked with the chromosome-3 marker gene kps (clubbed palpi) with a crossover value between 35% and 40%. In contrast to Aedes aegypti, where these two genes are close together on chromosome 2, in C. fatigans the dieldrin-resistance gene is separated on to chromosome 5.